System and method for an articulated arm based tool guide

ABSTRACT

A tool guide may be used with a computer-assisted medical device. The tool guide comprises an elongated body comprising a first end and a second end opposite the first end. The tool guide also comprises a joint attached to the first end of the elongated body and a mounting arm coupled to the elongated body via the joint. The tool guide also comprises a tool sleeve attached to the second end of the elongated body. The mounting arm is configured to be attached to a first articulated arm of the computer-assisted medical device, and the tool sleeve is adapted to receive an end effector attached to a second articulated arm of the computer-assisted medical device.

RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 15/522,657, filed Apr. 27, 2017 which is the U.S. nationalphase of International Application No. PCT/US15/58223 filed Oct. 30,2015 which claims priority to and the benefit of the filing date of U.S.Provisional Patent Application 62/072,612, entitled “SYSTEM AND METHODFOR AN ARTICULATED ARM BASED TOOL GUIDE,” filed Oct. 30, 2014, all ofwhich are incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to operation of devices witharticulated arms and more particularly to a tool guide for use witharticulated arms.

BACKGROUND

More and more devices are being replaced with autonomous andsemiautonomous electronic devices. This is especially true in thehospitals of today with large arrays of autonomous and semiautonomouselectronic devices being found in operating rooms, interventionalsuites, intensive care wards, emergency rooms, and the like. Forexample, glass and mercury thermometers are being replaced withelectronic thermometers, intravenous drip lines now include electronicmonitors and flow regulators, and traditional hand-held surgicalinstruments are being replaced by computer-assisted medical devices.

These electronic devices provide both advantages and challenges to thepersonnel operating them. Many of these electronic devices may becapable of autonomous or semi-autonomous motion of one or morearticulated arms and/or end effectors. When the articulated arms and/orthe end effectors include redundant degrees of freedom (i.e., more thanthe six degrees of freedom typically associated with Cartesian x, y, andz positioning and roll, pitch, and yaw orientations), the articulatedarms and/or the end effectors may provide extensive flexibility inadjusting to changes in patient size, position, and/or orientation asthe articulated arms and/or the end effectors are used to supportmedical procedures. This is possible because the redundant degrees offreedom allow the articulated arms and/or the end effectors to bepositioned so as to avoid collisions among themselves, the patient,and/or other devices and personnel in an operating room and/orinterventional suite.

Many medical procedures call for high precision in both the positioningand/or orientation of medical tools and/or devices. For example, medicalprocedures involving percutaneous ablation (including RF, cryo,microwave, and/or other forms of ablation), percutaneous needle biopsy,bone drilling, pedicle screw placement, seed planting, marker placement,medicine delivery, high magnification imaging, micro surgery, and/or thelike often call for very precise control of not only the position of adevice tool tip, but control over the orientation and/or advancement ofthe tool tip within a patient's anatomy.

Traditional approaches to the problem have relied on the skilled andsteady hands of medical personnel operating a respective medical device.However, even the most skilled and steady of practitioners may not beable to ensure adequate placement and/or orientation of the medicaldevice, especially, when significant force is used to advance the tooltip, such as when working in rigid anatomy, such as bones. Further, itmay be difficult for the medical personnel to easily adjust to movementsin the patient's anatomy and/or the patient or surgical table on whichthe patient is positioned.

Other approaches have relied on the use of tool jigs that are attachedto the patient or surgical table, mounted on table-side stands, mountedto ceiling fixtures, and/or the like. Many of these tool jigs, however,may have limitations in their degrees of freedom, size, and/or the likethat significantly limit their ability to be used with patients ofdifferent sizes, different positions within the anatomy of the patients,and/or with different procedures. These tool jigs may also have alimited ability to adapt to changes in patient position and/ororientation during a procedure. Additional flexibility may be obtainedby using different tool jigs for different procedures, but the number ofpossible patients, positions, and/or procedures may involve anunacceptably large number of tool jigs.

Accordingly, it would be advantageous to develop systems and methods forusing the flexibility of computer assisted articulated arms and/or endeffectors to provide a tool guide for medical devices.

SUMMARY

Consistent with some embodiments, a tool guide for use with articulatedarms includes an elongated body having a guide hole, a first jointattached to a first end of the body, a second joint attached to a secondend of the body opposite the first end, a first mounting arm coupled tothe body using the first joint, and a second mounting arm coupled to thebody using the second joint. The first mounting arm is configured to beattached to a first articulated arm of a computer-assisted medicaldevice. The second mounting arm is configured to be attached to a secondarticulated arm of the computer-assisted medical device. The guide holeis adapted to receive a medical tool and maintain a working end of themedical tool in alignment with the guide hole.

Consistent with some embodiments, a tool guide for use with articulatedarms includes an elongated body, a joint attached to a first end of thebody, a mounting arm coupled to the body using the joint, the mountingarm being configured to be attached to a first articulated arm of acomputer-assisted medical device, and a tool sleeve attached to a secondend of the body opposite the first end. The tool sleeve is adapted toreceive an end effector attached to a second articulated arm of thecomputer-assisted medical device. The tool guide is adapted to providegreater precision in positioning and orienting the end effector.

Consistent with some embodiments, a computer-assisted medical deviceincludes a control unit including one or more processors, a firstarticulated arm including one or more first joints, a second articulatedarm including one or more second joints, and a tool guide. The toolguide includes an elongated body having a guide hole, a third jointattached to a first end of the body, a fourth joint attached to a secondend of the body opposite the first end, a first mounting arm coupled tothe body using the third joint and coupling the tool guide to a distalend of the first articulated arm, and a second mounting arm coupled tothe body using the fourth joint and coupling the tool guide to a distalend of the second articulated arm. The guide hole is adapted to receivea working end of a medical tool. The control unit operates the first andsecond joints so as to position and align the guide hole in alignmentwith a target and steady the working end of the medical tool.

Consistent with some embodiments, a computer-assisted medical deviceincludes a control unit including one or more processors, a firstarticulated arm including one or more first joints, a second articulatedarm including one or more second joints, and a tool guide. The toolguide includes an elongated body, a third joint attached to a first endof the body, a mounting arm coupled to the body using the third jointand coupling the tool guide to a distal end of the first articulatedarm, and a tool sleeve attached to a second end of the body opposite thefirst end. The tool sleeve is adapted to receive an end effectorattached to the second articulated arm. The control unit operates thefirst joints to steady the end effector. And, the control unit operatesthe second joints to position and orient the end effector relative to atarget.

Consistent with some embodiments, a method of controlling motion of amedical tool includes determining an insertion path and a pose for amedical tool based on a target, deploying first and second articulatedarms of a computer-assisted medical device so that a distal end of eachof the first and second articulated arms are positioned and orientedrelative to each other based on a size and a shape of a tool guide,attaching the tool guide to first articulated arm and the secondarticulated arm using respective mounting arms of the tool guide,orienting a guide hole of the tool guide so as to align the guide holewith the insertion path, positioning the guide hole a desired distanceaway from the target based on the pose, placing the medical tool in theguide hole, and advancing the medical tool along the insertion path andtoward the target.

Consistent with some embodiments, a method of controlling motion of amedical tool includes determining an insertion path and a pose for themedical tool based on a target, attaching a tool guide to a firstarticulated arm of a computer-assisted medical device using a mount ofthe tool guide, inserting an end effector of a second articulated arm ofthe computer-assisted medical device in a tool sleeve of the tool guide,positioning and orienting the tool sleeve based on the insertion pathand the pose, attaching a second articulated arm to a mounting arm ofthe tool guide, advancing the end effector along the insertion path andtoward the target, and steadying the end effector using the secondarticulated arm and the tool guide.

Consistent with some embodiments, a non-transitory machine-readablemedium includes a plurality of machine-readable instructions which whenexecuted by one or more processors associated with a medical device areadapted to cause the one or more processors to perform a method. Themethod includes determining an insertion path and a pose for a medicaltool based on a target, deploying first and second articulated arms of acomputer-assisted medical device so that a distal end of each of thefirst and second articulated arms are positioned and oriented relativeto each other based on a size and a shape of a tool guide, attaching thetool guide to first articulated arm and the second articulated arm usingrespective mounting arms of the tool guide, orienting a guide hole ofthe tool guide so as to align the guide hole with the insertion path,positioning the guide hole a desired distance away from the target basedon the pose, placing the medical tool in the guide hole, and advancingthe medical tool along the insertion path and toward the target.

Consistent with some embodiments, a non-transitory machine-readablemedium includes a plurality of machine-readable instructions which whenexecuted by one or more processors associated with a medical device areadapted to cause the one or more processors to perform a method. Themethod includes determining an insertion path and a pose for the medicaltool based on a target, attaching a tool guide to a first articulatedarm of a computer-assisted medical device using a mount of the toolguide, inserting an end effector of a second articulated arm of thecomputer-assisted medical device in a tool sleeve of the tool guide,positioning and orienting the tool sleeve based on the insertion pathand the pose, attaching a second articulated arm to a mounting arm ofthe tool guide, advancing the end effector along the insertion path andtoward the target, and steadying the end effector using the secondarticulated arm and the tool guide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are simplified diagrams of a top and side view of a toolguide for use with two articulated arms and/or end effectors accordingto some embodiments.

FIG. 2 is a simplified diagram of a computer-assisted system accordingto some embodiments.

FIG. 3 is a simplified diagram of a kinematic model of acomputer-assisted medical system according to some embodiments.

FIG. 4 is a simplified diagram of a method of tool guide use accordingto some embodiments.

FIGS. 5A and 5B are simplified diagrams of a top and side view ofanother tool guide for use with two articulated arms and/or endeffectors according to some embodiments.

In the figures, elements having the same designations have the same orsimilar functions.

DETAILED DESCRIPTION

In the following description, specific details are set forth describingsome embodiments consistent with the present disclosure. It will beapparent to one skilled in the art, however, that some embodiments maybe practiced without some or all of these specific details. The specificembodiments disclosed herein are meant to be illustrative but notlimiting. One skilled in the art may realize other elements that,although not specifically described here, are within the scope and thespirit of this disclosure. In addition, to avoid unnecessary repetition,one or more features shown and described in association with oneembodiment may be incorporated into other embodiments unlessspecifically described otherwise or if the one or more features wouldmake an embodiment non-functional.

Computer-assisted systems with one or more articulated arms and/or endeffectors provide great flexibility to the operating room and/orinterventional suite. By providing computer control over the movement,position, and/or orientation of the articulated arms and/or the endeffectors, it is possible for the computer-assisted system to providesignificant advantages to both patients and medical personnel duringmedical procedures. In some examples, the computer-assisted systems maytake advantage of information in both pre-operative and intra-operativeimages to help position and/or orient the end effectors and/or devicesattached to the end effectors to desired positions within a patient'sanatomy. In some examples, the computer-assisted systems may furtherprovide guidance while a medical tool is being used during a procedure.

One possible use for a computer-assisted articulated arm and/or endeffector is to act as a guide for a medical tool, which is being usedduring a procedure. In some examples, a tool guide may be attached inplace of the end effector and/or at the end of the end effector. Thetool guide may be used to aid medical personnel in the positioning,orientation, and/or use of an associated medical tool. In some examples,the medical tool may be suitable for percutaneous ablation including RF,cryo, microwave, and/or other forms of ablation), percutaneous needlebiopsy, bone drilling, pedicle screw placement, seed planting, markerplacement, medicine delivery, high magnification imaging, micro surgery,and/or the like.

In some embodiments, however, use of a single articulated arm and/or endeffector with the tool guide may not provide adequate support for theassociated medical tool. In some examples, the single articulated armand/or end effector may not be able to provide sufficient stabilitywhile the associated medical tool is being operated. In some examples,the single articulated arm and/or end effector may have practical limitson the amount of force and/or torque that it may be able to apply to theassociated medical tool. In some examples, the single articulated armand/or end effector may have practical limits in positioning and/ororientation that may not be precise enough for the corresponding medicalprocedure. In some examples, the single articulated arm and/or endeffector may also be subject to small oscillations and/or vibrationsthat may be undesirable.

In some embodiments, a tool guide attached to two separate articulatedarms and/or end effectors may address many of the limitations of thesingle articulated arm and/or end effector tool guide. By attaching atool guide to the ends of two separate articulated arms and/or endeffectors, a closed kinematic chain through the two separate articulatedarms and/or end effectors and the tool guide may be formed. In someexamples, the closed kinematic chain may permit the computer-assistedsystem to obtain greater precision in position and/or orientation of thetool guide that would not otherwise be permitted with a singlearticulated arm and/or end effector. In some examples, the closedkinematic chain may also assist the two articulated arms and/or endeffectors to position the tool guide with greater rigidity and/orstiffness. In some examples, the closed kinematic chain may alsosignificantly reduce the small oscillations and/or vibrations of the twoarticulated arms and/or end effectors relative to a single articulatedarm and/or end effector arrangement.

FIGS. 1A and 1B are simplified diagrams of a top and side view of a toolguide 100 for use with two articulated arms and/or end effectorsaccording to some embodiments. As shown in FIGS. 1A and 1B, tool guide100 includes a rigid or mostly rigid body 110 with an elongated shape.At some position along body 110, a guide hole 120 is provided for amedical tool. In some examples, guide hole 120 may be placed near acenter of body 110 to help maximize the amount of clearance around guidehole 120 and between the two articulated arms and/or end effectorssupporting tool guide 100. In some examples, guide hole 120 may have adiameter so as to provide a slip fit for the medical tool being guidedby tool guide 100. In some examples, a thickness of body 110 in theaxial direction of guide hole 120 (i.e., the direction of arrow 150) maybe suitable to provide lateral stability to the medical tool beingguided by tool guide 100. In some examples, the thickness of body 110may be at least 1.5 cm in length and/or 3 cm in length or longer.Although not shown in FIGS. 1A and 1B, a bushing and/or elastomericmaterial may be inserted into guide hole 120 between body 110 and themedical tool to help reduce the transmission of vibrations from themedical tool to tool guide 110. And although, tool guide 100 is shownwith only a single guide hole 120, additional guide holes may beincluded as appropriate for the medical tool being guided. Although thebody 110 is shown to have an elongated shape, it may be shaped as a gridwith a plurality of holes, which can be used for applications such asbrachytherapy.

Tool guide 100 further includes joints 130 at ends of body 110 thatcouple body 110 to respective mounting arms 140. As shown in FIGS. 1Aand 1B, the joints 130 include two degree of freedom universal jointsallowing independent rotation of mounting arms 140 relative to body 110along two separate axes. In some examples, the inclusion of the joints130 adds additional degrees of freedom to a closed kinematic chainincluding tool guide 100. In some examples, these additional degrees offreedom may provide greater flexibility in positioning the articulatedarms and/or end effectors that are holding tool guide 100 so as toincrease the potential clearance between guide hole 120 and thearticulated arms and/or end effectors. And although FIGS. 1A and 1Bdepict the joints 130 as two degree of freedom universal joints, otherconfigurations are possible. In some examples, the joints 130 may beball-in-socket joints. In some examples, the joints 130 may include zeroand/or one degree of freedom and/or may include a more complexarrangement of joints and links providing for more than two degrees offreedom. In some examples, the joints 130 may be passive, may includevarying levels of resistance to motion, and/or may include one or moreactuators making them active joints. In some embodiments, the joints 130may include one or more sensors for determining a position, orientation,force, and/or torque of the joints 130. In some examples either of thejoints 130 may be lockable (e.g., by a manually-tightened frictionfeature) to temporarily prevent the respective joint 130 from moving. Insome embodiments, the joints 130 may benefit from a variable stiffnessjoint mechanism using materials and techniques such aselectro-rheological (ER) and/or magneto-rheological (MR) fluids.

In some embodiments, mounting arms 140 may include one or more featuresto help support use of tool guide 100 with the articulated arms and/orend effectors. In some examples, the ends of mounting arms 140 oppositethe joints 130 may include a standardized attachment arrangementdesigned to mate with specific articulated arms and/or endeffectors—such as a standardized structure used to mount a cannulaand/or a guide tube on a single articulated arm. In some examples, thestandardized attachment may provide a rigid, non-slip attachment betweentool guide 100 and the articulated arms and/or end effectors. In someexamples, mounting arms 140 may include one or more notches, flanges,clips, and/or the like suitable for attaching each of the mounting arms140 to a respective articulated arm and/or end effector. In someexamples, by attaching tool guide 100 to the articulated arms using themounting arms 140, tool guide 100 becomes a shared end effector for thearticulated arms. In some examples, mounting arms 140 may each includesuitable identifying features so the articulated arm and/or end effectorto which the mounting arm 140 is attached may identify the mounting arm140 as belonging to tool guide 100 and may further identify a modelnumber of tool guide 100. In some examples, the identifying features mayinclude one or more physical patterns, electrical contacts, magnets,RFID devices, and/or the like. In some examples, mounting arms 140 mayfurther include electrical and/or physical contacts for allowing thearticulated arms and/or end effectors to read the sensors and/or commandthe actuators in the joints 130.

The configuration of tool guide 100 may be used to determine a kinematicmodel that may be used to describe the constrained kinematicrelationship between the articulated arms and/or end effectors holdingtool guide 100. The kinematic model of tool guide 100 is subject to thefollowing constraints: (1) a fixed length of body 110 between pivotpoints 160 and 165, along the axis 170, (2) body 110 may not be twisted,therefore the rotation angle around axis 170 should be the same at bothpivot points 160 and 165, (3) angles around axes 180 and 190 at pivotpoint 160 and angles around axes 185 and 195 at pivot point 165 shouldbe within corresponding joint limits of joints 130. These kinematicconstraints on tool guide 100 pose 6 equations, which uniquely determinethe relationship between coordinate frames of the articulated armsand/or end effectors holding tool guide 100.

In some embodiments, tool guide 100 may further include a memory device(not shown). In some examples, the memory device may be used to storeinformation associated with tool guide 100 including tool guide type,tool guide identification number, tool guide model number, tool guidekinematic parameters, and/or the like. In some examples, the storedinformation may be read by the computer-assisted system upon connectionof either of the mounting arms 140 to one of the articulated arms and/orone of the end effectors. In some examples, the read information may beused by the computer-assisted system to identify tool guide 100, setcontrol parameters, access the kinematic parameters, and/or the like. Insome examples, the memory device may be accessed using the electricalcontacts, RF communication, and/or the like. In some examples, thememory device may include a machine readable media, such as RAM, PROM,EPROM, FLASH-EPROM, any other memory chip or cartridge, and/or any othermedium from which a processor or computer is adapted to read.

In some embodiments, the mounting arms 140 may be used to provideelectrical power to tool guide 100. In some examples, the electricalpower may be used to operate the sensors, drive the actuators, controlstiffness of the joints 130 via ER and/or MR fluids, and/or the like.

According to some embodiments, while tool guide 100 is in use, guidehole 120 may be positioned above target anatomy of a patient and alignedso that the axial direction of guide hole 120 is aligned to the targetanatomy. Once in position and alignment, the medical tool may beinserted through guide hole 120 in the direction indicated by arrow 150.In some examples, a working end (such as a needle, drill bit, tube,shaft, and/or other element) of the medical tool may be inserted throughguide hole 120 in the direction of arrow 150 so that the working end ismaintained in alignment with the target anatomy. In some examples, body110 of tool guide 100 may also act as a stop for the medical tool thatprohibits at least some portion of the medical tool, larger than guidehole 120 from advancing beyond body 110.

FIG. 2 is a simplified diagram of a computer-assisted system 200according to some embodiments. As shown in FIG. 2 , computer-assistedsystem 200 includes a computer-assisted medical device supportingmultiple articulated arms. In some embodiments, the computer-assistedmedical device and an operator workstation (not shown) may correspond toa da Vinci® Surgical System commercialized by Intuitive Surgical, Inc.of Sunnyvale, Calif. The computer-assisted medical device includes abase 210. In some examples, base 210 may include one or more wheelsand/or may be mounted on a track to facilitate positioning of thecomputer-assisted medical device within an operating room,interventional suite, and/or adjacent to a patient table. To facilitatepositioning of the articulated arms of the computer-assisted medicaldevice, a set-up structure 220 may be mounted on base 210. The set-upstructure 220 may include one or more joints and/or links that may beused to adjust a position, orientation, and/or height of an articulatedarm gantry 230. In some examples, gantry 230 may be positioned over apatient table. In some examples, set-up structure 220 may furtherinclude one or more sensors and/or the like to allow computer-assistedsystem 200 to determine a forward and/or inverse kinematic transformcharacterizing the position and/or orientation of gantry 230 relative tobase 210. In some examples, set-up structure 220 may further include oneor more actuators and/or the like to allow computer-assisted system 200to change the position and/or orientation of gantry 230 relative to base210 and set-up structure 220.

Attached to gantry 230 are several articulated arms 240, 250, and 260.And although FIG. 2 shows three articulated arms 240, 250, and 260attached to gantry 230, other configurations may include only twoarticulated arms, and additional articulated arms may also be present.Each of the articulated arms 240, 250, and 260 may include one or morejoints and links between the proximal end attached to gantry 230 and thedistal end to which a respective end effector, tool, imaging device,tool guide, medical tool, and/or the like are attached. In someexamples, each of the articulated arms 240, 250, and 260 may furtherinclude one or more sensors and/or the like to allow computer-assistedsystem 200 to determine a forward and/or inverse kinematic transformcharacterizing the position and/or orientation of the distal end of therespective articulated arm 240, 250, and/or 260 relative to gantry 230.In some examples, each of the articulated arms 240, 250, and 260 mayfurther include one or more sensors for determining forces and/ortorques being applied to the joints and/or links of the respectivearticulated arm 240, 250, and/or 260. In some examples, each of thearticulated arms 240, 250, and 260 may further include one or moreactuators and/or the like to allow computer-assisted system 200 tochange the position and/or orientation of respective end effectors atthe distal ends of each of the articulated arms 240, 250, and 260relative to gantry 230.

As shown in FIG. 2 , a first mounting arm 140 of a tool guide isattached to the distal end of articulated arm 240 and a second mountingarm 140 of the tool guide is attached to the distal end of articulatedarm 250. The resulting structure creates a closed kinematic loop betweengantry 230, through articulated arm 240, the mounting arms 140, joints130, and body 110 of the tool guide, through articulated arm 250, andback to gantry 230. In some examples, the closed kinematic loop may beused to provide stability in the position and/or orientation of guidehole 120 over target anatomy of a patient. In some examples, the closedkinematic loop may be used to provide higher stiffness for the toolguide 100 relative to the stiffness of a single articulated armapproach.

As further shown in FIG. 2 , an imaging device 270 may be attached tothe distal end of articulated arm 260. In some examples, imaging device270 may be an endoscope, an ultrasound device, and/or the like. In someexamples, imaging device 270 may provide one or more images of thetarget anatomy to facilitate the use of a medical tool inserted throughguide hole 120. In some examples, when imaging device 270 includesstereoscopic and/or other three-dimensional imaging capabilities,imaging device 270 may be used to determine a kinematic relationshipbetween gantry 230 and the target anatomy. In some examples, thiskinematic relationship may be useful in positioning and/or orientingguide hole 120 and the tool guide relative to the target anatomy.

The computer-assisted medical device is coupled to a control unit 280via an interface. The interface may include one or more cables,connectors, and/or buses and may further include one or more networkswith one or more network switching and/or routing devices. Control unit280 includes a processor 285 coupled to memory 290. Operation of controlunit 280 is controlled by processor 285. And although control unit 280is shown with only one processor 285, it is understood that processor285 may be representative of one or more central processing units,multi-core processors, microprocessors, microcontrollers, digital signalprocessors, field programmable gate arrays (FPGAs), application specificintegrated circuits (ASICs), and/or the like in control unit 280.Control unit 280 may be implemented as a stand-alone subsystem and/orboard added to a computing device or as a virtual machine. In someembodiments, control unit 280 may be included as part of an operatorworkstation (not shown) for allowing medical personnel to control and/oroperate computer-assisted system 200. In some examples, control unit 280may be operated separately from, but in coordination with the operatorworkstation.

Memory 290 may be used to store software executed by control unit 280and/or one or more data structures used during operation of control unit280. Memory 290 may include one or more types of machine readable media.Some common forms of machine readable media may include floppy disk,flexible disk, hard disk, magnetic tape, any other magnetic medium,CD-ROM, any other optical medium, punch cards, paper tape, any otherphysical medium with patterns of holes, RAM, PROM, EPROM, FLASH-EPROM,any other memory chip or cartridge, and/or any other medium from which aprocessor or computer is adapted to read.

As shown, memory 290 includes a motion control application 295 that maybe used to support autonomous and/or semiautonomous control ofcomputer-assisted system 200. Motion control application 295 may includeone or more application programming interfaces (APIs) for receivingposition, motion, and/or other sensor information from the sensors inset-up structure 220, the articulated arms 240, 250, and/or 260, and/orthe tool guide as will be discussed in further detail below. In someexamples, motion control application 295 may receive one or morepre-operative images, intra-operative images, images from imaging device270, and/or the like as will be discussed in further detail below. Insome examples, motion control application 295 may support the autonomousand/or semi-autonomous motion of articulated arms 240, 250, and/or 260to help position and/or orient the tool guide as will be discussed infurther detail below. In some examples, motion control application 295may also exchange position, motion, and/or collision avoidanceinformation with other control units regarding other devices, and/orplanning and/or assisting in the planning of motion forcomputer-assisted system 200, articulated arms 240, 250, and/or 260,and/or the like. And although motion control application 295 is depictedas a software application, motion control application 295 may beimplemented using hardware, software, and/or a combination of hardwareand software.

FIG. 3 is a simplified diagram of a kinematic model 300 of acomputer-assisted medical system according to some embodiments. As shownin FIG. 3 , kinematic model 300 may include kinematic informationassociated with many sources and/or devices. In some embodiments, beforea medical procedure is performed, it is common for one or morepre-operative images to be obtained. In some examples, thesepre-operative images may include a series of tomographic images that maybe used to develop a three-dimensional model of the patient's anatomy.In some examples, the pre-operative images may be taken via computedtomography (CT), magnetic resonance imaging (MRI), and/or the like. Insome examples, medical personnel may review the pre-operative images todevelop a plan for a medical procedure that may identify one or moretargets (e.g., positions for needle ablation, biopsy, seed positions,drilling points, pedicle screw positions, and/or the like). In someexamples, the plan may also identify one or more no-fly zones that maybe used to protect patient anatomy during the medical procedure. In someexamples, the pre-operative images, as well as the targets and/or no-flyzones may be established in a pre-operative image coordinate system 305.In some examples, the pre-operative image coordinate system 305 may bedetermined in part by a coordinate system and/or one or more kinematicmodels associated with the one or more imaging devices taking thepre-operative images.

In some embodiments, once the patient is positioned and oriented for themedical procedure, one or more intra-operative images may be obtained todetermine the position and/or orientation of the patient for the medicalprocedure. In some examples, the intra-operative images may include twoor more x-rays obtained along non-parallel axes. In some examples, thenon-parallel axes may have an angular separation of at least 30 degrees.In some examples, the x-ray images may be lateral and anterior-posteriorimages of the patient. In some examples, the intra-operative images mayuse other imaging technology that identifies three-dimensionalinformation and may include ultrasound, bi-plane fluoroscopy,stereoscopic fluorescence imaging, and/or the like. In some examples, anintra-operative patient coordinate system 310 may be determined in partby a coordinate system and/or one or more kinematic models associatedwith the one or more imaging devices taking the intra-operative images.

In some embodiments, medical personnel may review the intra-operativeimages to determine positions of the targets identified as part of theplan using the pre-operative images. In some examples, one or moreno-fly zones may also be identified in the intra-operative images. Insome examples, positions of one or more markers and/or identifiedanatomical features may be located using the intra-operative images. Insome examples, the intra-operative images, as well as the targets,no-fly zones, features, and/or markers may be established in theintra-operative patient coordinate system 310.

In some embodiments, the patient may be located on a patient table thatmay be positioned and/or oriented by medical personnel. In someexamples, a height of the patient table above the floor may be adjusted.In some examples, an orientation of the patient table may be adjustedalong one or more roll, pitch, yaw, and/or the like axes. In someexamples, the position and/or orientation of the patient table may beestablished in a table coordinate system 315.

In some embodiments, a computer-assisted medical device, such as thecomputer-assisted medical device of FIG. 2 , may be used during themedical procedure. In some examples, the position and/or orientation ofa base of the computer-assisted medical device may be adjusted relativeto the patient table. In some examples, the computer-assisted medicaldevice may be established in a device-base coordinate system 320.

In some embodiments, the computer-assisted medical device may include aset-up structure, such as set-up structure 220, to adjust a position andorientation of a gantry to which one or more articulated arms areattached. In some examples, the gantry may be similar to gantry 230. Insome examples, the gantry may be established in an arm gantry coordinatesystem 325.

In some embodiments, a plurality of articulated arms may be attached tothe gantry. Each of the articulated arms may include one or more jointsand/or links with the joints and/or links establishing a coordinatesystem 330, 335, and/or 340 at a distal end of each of the articulatedarms and/or an end effector at the distal end of a respectivearticulated arm. In some examples, the articulated arms associated witharm coordinate systems 330 and 335 may correspond to articulated arms240 and 250 and the articulated arm associated with arm coordinatesystem 340 may correspond to articulated arm 260.

In some embodiments, a tool guide, such as tool guide 100, may becoupled between the articulated arms associated with arm coordinatesystems 330 and 335. In some examples, the tool guide and/or a guidehole of the tool guide may be established in a tool guide coordinatesystem 350.

In some embodiments, an imaging device may be coupled to the distal endof the articulated arm associated with arm coordinate system 340. Insome examples, the imaging device may be an endoscope, an ultrasounddevice, a microscope, and/or the like. In some examples, the imagingdevice may include stereoscopic and/or other three-dimensionalpositioning capabilities for mapping observed images to arm coordinatesystem 340.

In some embodiments, kinematic modeling and/or one or more registrationprocesses may be used to establish the kinematic relationships betweenthe various coordinate systems 305-350. In some examples, the kinematicmodeling and/or registration processes may be used to establishtransformation matrices between the various coordinate systems 305-350to permit the forward and/or reverse mapping of positions and/ororientations in one of the coordinate systems 305-350 to another of thecoordinate systems 305-350.

In some embodiments, a registration process may be used to determine apre-operative to intra-operative kinematic relationship 355 between thepre-operative coordinate system 305 and the intra-operative patientcoordinate system 310. In some examples, the registration process mayinclude identifying common image elements in the pre-operative andintra-operative images (e.g., unique and/or unusual anatomical features,markers, and/or the like), locating the common image elements in boththe pre-operative image and intra-operative patient coordinate systems305, 310, and using the differences between the positions and/ororientations of the common image elements to determine the translations,scales, and/or rotations between the pre-operative image coordinatesystem 305 and the intra-operative coordinate system 310. Thetranslations, scales, and/or rotations may be used to determine thepre-operative to intra-operative kinematic relationship 355. In someexamples, the pre-operative to intra-operative kinematic relationship355 may be used to transform the targets and/or no-fly zones identifiedduring the pre-operative plan from the pre-operative image coordinatesystem 305 to the intra-operative patient coordinate system 310. In someexamples, the pre-operative to intra-operative kinematic relationship355 may include multiple transformations that apply to sub-regionswithin the pre-operative and intra-operative coordinate systems 305 and310 to account for changes in the patient's anatomy between a pose usedfor the pre-operative images and the pose used for the intra-operativeimages. In some examples, the sub-regions may account for changes inpositions of the patient's joints, vertebrae, and/or the like betweenthe pre-operative and intra-operative poses.

In some embodiments, a patient to table kinematic relationship 360between the patient (i.e., the intra-operative patient coordinate system310) and the patient table (i.e., the table coordinate system 315) maynot be directly determined. However, a closed kinematic chain may beused to determine the patient to table kinematic relationship 360 as isdiscussed in further detail below.

In some embodiments, a table to device-base kinematic relationship 365may be determined using a registration process between the patient tableand the computer-assisted medical device. Methods and approaches forestablishing the table to device-base kinematic relationship aredescribed in greater detail in U.S. Patent Application No. 61/954,538(filed Mar. 17, 2014) (entitled “Methods and Systems for Tele-SurgicalTable Registration”), which is hereby incorporated by reference for allpurposes.

In some embodiments, a set-up structure kinematic relationship 370between the device-base coordinate system 320 and the arm gantrycoordinate system 325 may be determined by using one more kinematicmodels of the set-up structure coupling the device base to the gantry.In some examples, one or more sensors located in the set-up structuremay be used to determine the coordinate transformation associated withthe set-up structure kinematic relationship 370. In some examples, theset-up structure kinematic relationship 370 may be updated as the gantryis moved to different positions and/or orientations relative to thedevice base coordinate system 320.

In some embodiments, corresponding articulated arm kinematicrelationships 372 and 374 between the arm gantry coordinate system 325and the articulated arm coordinate systems 330 and 335, respectively,may be determined by using one or more kinematic models of thearticulated arms and/or end effectors coupling the gantry to a distalend of the corresponding articulated arms and/or end effectors. In someexamples, one or more sensors located in the articulated arms and/or endeffectors may be used to determine the coordinate transformationassociated with the corresponding articulated arm kinematicrelationships 372 and 374. In some examples, the articulated armkinematic relationships 372 and 374 may be updated as the articulatedarms and/or end effectors are moved to different positions and/ororientations relative to the arm gantry coordinate system 325.

In some embodiments, corresponding tool guide kinematic relationships376 and 378 between the respective arm coordinate systems 330 and 335and the tool guide coordinate system 350 may be determined by using theclosed kinematic loop through the tool guide and the kinematics of thejoints (e.g., joints 130) and body (e.g., body 110) of the tool guide.Even when the joints of the tool guide are passive and may not havejoint actuators, the closed kinematic loop of the two articulated armscoupled to the tool guide permits determination of the tool guidekinematic relationships 376 and 378. In some examples, the articulatedarm kinematic relationships 372 and 374 may be used to determine aposition and an orientation of the connection points of the tool guideto both of the articulated arms in the same articulated arm coordinatesystem 330 or 335. Consider the case where the tool guide 100 isattached to articulated arms 240 and 250 with corresponding coordinatesystems 330 and 335. In order to determine the kinematic relationships376 and 378, the constrained kinematic equation between coordinatesystems 330 and 335 may be solved in such a way that it satisfies thefollowing conditions: (1) a fixed length of body 110 between pivotpoints 160 and 165, along axis 170, (2) body 110 may not be twisted,therefore the rotation angle around axis 170 should be the same at bothpivot points 160 and 165, (3) angles around axes 180 and 190 at pivotpoint 160 and angles around axes 185 and 195 at pivot point 165 shouldbe within corresponding joint limits of joints 130. These constraintspose 6 equations, which uniquely determine the coordinate frame 350given the coordinate frames 330 and 335, which are known from forwardkinematic models of the arms 240 and 250; by solving these equations,kinematic relationships 376 and 378 between coordinate frames 330 and350 and between coordinate frames 335 and 350 may be determined.

In some embodiments, an articulated arm kinematic relationship 380between the arm gantry coordinate system 325 and the articulated armcoordinate system 340 may be determined by using one or more kinematicmodels of the articulated arm and/or end effector coupling the gantry toa distal end of the articulated arm and/or end effector. In someexamples, one or more sensors located in the articulated arm and/or endeffector may be used to determine the coordinate transformationassociated with the articulated arm kinematic relationship 380. In someexamples, the articulated arm kinematic relationship 380 may be updatedas the articulated arm and/or end effector are moved to a differentposition and/or orientation relative to the gantry coordinate system325.

In some embodiments, when an imaging device coupled to the articulatedarm associated with the articulated arm coordinate system 340 is able toobserve the features and/or markers located in the intra-operativepatient coordinate system 310, it is possible to determine a patientkinematic relationship 385 between the articulated arm coordinate system340 and the anatomy of the patient. In some examples, image processingof one or more images obtained by the imaging device may be used todetermine positions and/or orientations of the features and/or markerson the anatomy of the patient in articulated arm coordinate system 340and, thus, determine the patient kinematic relationship 385. In someexamples, the positions and/or orientations of the targets and no-flyzones regions in the intra-operative patient coordinate system 310 maybe mapped to the articulated arm coordinate system 340 by using thepatient kinematic relationship 385.

In some embodiments, a closed kinematic chain through theintra-operative patient coordinates 310, patient kinematic relationship385, articulated arm coordinate system 340, articulated arm kinematicrelationship 380, arm gantry coordinate system 325, one of thearticulated arm kinematic relationships 372 or 374, a corresponding oneof the articulated arm coordinate systems 330 or 335, a correspondingone of the tool guide kinematic relationships 376 or 378, and the toolguide coordinate system 350 may be used to determine a tool to targetkinematic relationship 390 by suitable application of the inverse andforward kinematic relationships. In some examples, the tool to targetkinematic relationship 390 may be used to quickly convert the positionand orientation of the guide hole of the tool guide in the tool guidecoordinate system 350 to the intra-operative patient coordinate system310 so as to effectively control the alignment of the guide hole withthe target while providing an insertion axis which may avoid the no-flyzones.

In some embodiments, the patient to table kinematic relationship 360 mayalso be determined using the closed kinematic loop through the table todevice-base kinematic relationship 365, the set-up kinematicrelationship 370, the articulated arm kinematic relationship 380, andthe patient kinematic relationship 385.

In some embodiments, the various kinematic relationships 355-390 mayalso be used to support collision avoidance when using thecomputer-assisted medical device. In some examples, the kinematicrelationships (e.g., kinematic relationships 372, 374, 376, 378, and/or380) may be used to help avoid collisions between the variousarticulated arms, such as between the articulated arms holding the toolguide and the articulated arm holding the imaging device used toestablish the patient kinematic relationship 385. In some examples, thekinematic relationships (e.g., kinematic relationships 360-390) may beused to prevent the articulated arms from entering the no-fly zones inthe intra-operative patient coordinate system 310 and/or the patienttable.

FIG. 4 is a simplified diagram of a method 400 of tool guide useaccording to some embodiments. One or more of the processes 405-480 ofmethod 400 may be implemented, at least in part, in the form ofexecutable code stored on non-transient, tangible, machine readablemedia that when run by one or more processors (e.g., the processor 285in control unit 280) may cause the one or more processors to perform oneor more of the processes 405-480. In some embodiments, the method 400may be performed by an application, such as motion control application295. In some embodiments, processes 415, 430, and/or 455 are optionaland may be omitted.

At a process 405, one or more pre-operative images are loaded. In someembodiments, a surgical plan is determined upon review of the one ormore pre-operative images. In some examples, the one or morepre-operative images may be images of a desired portion of a patient'sanatomy. In some examples, the one or more pre-operative images mayinclude one or more slices and/or other three-dimensional information ofthe patient's anatomy. In some examples, the one or more pre-operativeimages may be obtained from a tomographic imaging device such as a CT,MRI, and/or similar imaging device. In some examples, the one or morepre-operative images may be associated with a pre-operative imagecoordinate system, such as pre-operative image coordinate system 305.During process 405, at least one of the pre-operative images is loadedfor display to medical personnel.

At a process 410, a target is selected. In some embodiments, the medicalpersonnel may review the one or more pre-operative images loaded duringprocess 405 to determine a target for a medical procedure. In someexamples, the target may be selected using a pointing device on thepre-operative image loaded during process 405. In some examples, thetarget may be associated with a portion of a patient's anatomy that isto be the subject of percutaneous ablation including RF, cryo,microwave, and/or other forms of ablation), percutaneous needle biopsy,bone drilling, pedicle screw placement, seed planting, marker placement,medicine delivery, high magnification imaging, micro surgery, and/or thelike. In some examples, the target may be located within thepre-operative image coordinate system.

At an optional process 415, one or more no-fly zones are selected. Insome embodiments, the medical personnel may further review the one ormore pre-operative images loaded during process 405 to determine one ormore no-fly zones within the one or more pre-operative images. In someexamples, the one or more no-fly zones may be selected using a pointingdevice on the pre-operative image loaded during process 405. In someexamples, the one or more no-fly zones may correspond with one or moreregions of the patient's anatomy, which are to be avoided by acomputer-assisted surgical system and/or one or more medical tools. Insome examples, the one or more no-fly zones may be located within thepre-operative image coordinate system.

At a process 420, the patient is posed. In some embodiments, the patientmay be prepared for a medical procedure and then posed on a patienttable. In some examples, once the patient is posed, the particular posemay be associated with an intra-operative patient coordinate system,such as intra-operative patient coordinate system 310. In some examples,the patient table may be associated with a table coordinate system, suchas table coordinate system 315.

At a process 425, the one or more pre-operative images are registered toone or more intra-operative images. In some embodiments, once thepatient is posed for the medical procedure during process 420, one ormore intra-operative images may be obtained to determine the positionand/or orientation of the patient for the medical procedure. In someexamples, the intra-operative images may include two or more x-raysobtained along non-parallel axes. In some examples, the non-parallelaxes may have an angular separation of at least 30 degrees. In someexamples, the x-ray images may be lateral and anterior-posterior imagesof the patient. In some examples, the intra-operative images may useother imaging technology that identifies three-dimension information andmay include ultrasound, bi-plane fluoroscopy, stereoscopic fluorescenceimaging, and/or the like. In some examples, the one or moreintra-operative images may be associated with the intra-operativepatient coordinate system.

In some examples, the registration may be used to determine apre-operative to intra-operative kinematic relationship, such as theintra-operative kinematic relationship 355 between the pre-operativecoordinate system 305 and the intra-operative patient coordinate system310. In some examples, the registration process may include automatedand/or semi-automated identification of one or more common imageelements in the one or more pre-operative images and the one or moreintra-operative images (e.g., one or more unique and/or unusualanatomical features, markers, and/or the like), locating the one or morecommon image elements in both the pre-operative image andintra-operative patient coordinate systems, and using the differencesbetween the positions and/or orientations of the one or more commonimage elements to determine the translations, scales, and/or rotationsbetween the pre-operative image coordinate system and theintra-operative patient coordinate system. The translations, scales,and/or rotations may be used to determine the pre-operative tointra-operative kinematic relationship. In some examples, thepre-operative to intra-operative kinematic relationship may be used totransform the target selected during process 410 and/or the one or moreno-fly zones selected during process 415 from the pre-operative imagecoordinate system to the intra-operative patient coordinate system. Insome examples, the user may update the target position and/or the no-flyzones based on the intra-operative patient pose. In some examples, thepre-operative to intra-operative kinematic relationship may includemultiple transformations that apply to sub-regions within thepre-operative and intra-operative coordinate systems to account forchanges in the patient's anatomy between a pose used for the one or morepre-operative images loaded during process 405 and the pose used for theone or more intra-operative images. In some examples, the sub-regionsmay account for changes in positions of the patient's joints, and/or thelike between the pre-operative and intra-operative poses.

At an optional process 430, a computer-assisted medical device isregistered to the patient table. In some embodiments, a table to medicaldevice kinematic relationship, such as the table to device-basekinematic relationship 365, may be determined using a registrationprocess between the patient table and the computer-assisted medicaldevice. Methods and approaches for establishing the table to medicaldevice kinematic relationship are described in greater detail in U.S.Patent Application No. 61/954,538, incorporated by reference above.

At a process 435, the computer-assisted medical device is registered tothe patient. In some embodiments, registering of the computer-assistedmedical device with the patient may begin with the acquisition of one ormore computer-assisted medical device based images. The one or morecomputer-assisted medical device based images may be obtained todetermine the position and/or orientation of the patient relative to thecomputer-assisted medical device. In some examples, the one or morecomputer-assisted medical device based images may be obtained by usingan imaging device mounted on the computer-assisted medical device. Insome examples, the one or more computer-assisted medical device basedimages may be obtained using imaging device 270 mounted at the distalend of an articulated arm (e.g., articulated arm 260) of thecomputer-assisted medical device. In some examples, the image device maybe an endoscope, an ultrasound device, and/or the like. In someexamples, the one or more computer-assisted medical device based imagesmay provide one or more images of the patient's anatomy associated withone or more features and/or targets with known coordinates in theintra-operative patient coordinate system.

In some examples, the registration may be used to determine a patient tocomputer-assisted medical device kinematic relationship, such as thepatient kinematic relationship 385 between the intra-operativecoordinate system 310 and the articulated arm coordinate system 340. Insome examples, the registration process may include automated and/orsemi-automated identification of the one or more features and/or targetsin the one or more computer-assisted medical device based images and theone or more intra-operative and/or one or more pre-operative images andusing the differences between the positions and/or orientations of theone or more features and/or targets to determine the translations,scales, and/or rotations between the intra-operative patient coordinatesystem and the articulated arm coordinate system. The translations,scales, and/or rotations may be used to determine the patient tocomputer-assisted medical device kinematic relationship. In someexamples, the patient to computer-assisted medical device kinematicrelationship may be used to transform the target selected during process410 and/or the one or more no-fly zones selected during process 415 fromthe intra-operative patient coordinate system to the articulated armcoordinate system. In some examples, additional coordinate systems(e.g., coordinates systems 320, 325, 330, and/or 335) and theirkinematic relationships (e.g., kinematic relationships 370, 372, 374,and/or 380) may be used to transform the target selected during process410 and/or the one or more no-fly zones selected during process 415 fromthe intra-operative patient coordinate system to one or more of theadditional coordinate systems.

At a process 440, a medical tool insertion path and pose is determined.In some embodiments, once the computer-assisted medical device isregistered to the patient during process 435, the insertion path and thepose of the medical tool to be used during the medical procedure may bedetermined. In some examples, the various kinematic relationships of thecomputer-assisted medical device (e.g., kinematic relationships 370,372, 374, and/or 380) along with the patient to computer-assistedmedical device kinematic relationship may be used to determine aninsertion path and a pose for the medical tool that aligns the tool withthe target selected during process 410 and allows insertion of themedical tool along the insertion path and toward the target withoutintersecting any of the one or more no-fly zones determined duringprocess 415. In some examples, determination of the medical toolinsertion path and pose may further include determining a positionand/or orientation of a guide hole of a tool guide, such as guide hole120 of tool guide 100, and/or desired joint positions for thearticulated arms of the computer-assisted medical device that are usedto hold the tool guide. In some examples, determination of the medicaltool insertion path and pose may be an iterative process in which aproposed medical tool insertion path and pose are shown to medicalpersonnel with the medical personnel being able to make adjustments tothe insertion path and/or pose. In some examples, the proposed medicaltool insertion path and pose may be shown to the medical personnel as anoverlay on the one or more intra-operative images obtained duringprocess 425, the one or more pre-operative images loaded during process405, and/or the one or more computer-assisted medical device basedimages obtained during process 435.

At a process 445, the articulated arms that are used to hold the toolguide are deployed. In some examples, positioning and/or orientation ofthe articulated arms that are used to hold the tool guide may be acomplex task that may not be practical either by manual manipulation ofthe articulated arms in a clutched mode and/or via teleoperation. Insome examples, the computer-assisted medical system may plan and executemotion plans for the articulated arms that are used to hold the toolguide so as to place them in a suitable position and/or orientation forattaching the tool guide. In some examples, the suitable position and/ororientation may be approximately located where the tool guide is to bepositioned and/or oriented as determined during process 440. In someexamples, the suitable position and/or orientation may be somewhatfarther apart than the actual size of the tool guide to allow for extraclearance between the distal ends of the articulated arms that are toreceive the mounting arms of the tool guide, such as the mounting arms140 of tool guide 100. In some examples, the deployment plan may furtherinclude determining one or more collision avoidance paths with otherarticulated arms of the computer-assisted medical device (e.g., thearticulated arm to which the imaging device of process 435 is mounted),the set-up structure of the computer-assisted medical device, thepatient, and/or the like. In some examples, the deployment plan may alsoinclude planned motions to move the other articulated arms and/or theset-up structure of the computer-assisted medical device out of the wayof the articulated arms that are holding the tool guide. In someexamples, during deployment, forces and/or torques in the articulatedarms may be monitored in order to detect unforeseen collisions withother objects, personnel, and/or the like in the vicinity of thecomputer-assisted medical device. In some examples, the deployment mayinclude activating one or more actuators in the articulated arms and/orthe set-up structure of the computer-assisted medical device bycontrolling one or more voltages, currents, duty cycles, and/or thelike. In some examples, the deployment may be triggered by medicalpersonnel using an activation button located on one of the articulatedarms, via an operator workstation, and/or the like.

At a process 450, the tool guide is attached. In some embodiments, eachof the mounting arms of the tool guide is mounted on a distal end of acorresponding one of the articulated arms. In some examples, theattaching of the tool guide may include inserting one or more flanges,pins, and/or the like into corresponding receiving notches, holes,and/or the like on the articulated arms. In some examples, the attachingof the tool guide may include one or more medical personnel manuallymoving the tool guide and/or the articulated arms. In some examples, thearticulated arms may be placed in a clutched and/or unlocked state toallow manual movement of the joints of the articulated arm, and/or maybe placed in a resistive state allowing the joints of the articulatedarms to be moved, but with some resistance so as to avoid excessivemovement of the articulated arms.

At an optional process 455, the tool guide is initially placed. In someembodiments, once the computer-assisted medical device detects theattachment of an appropriate tool guide (e.g., using the identifyingfeatures of the tool guide), the articulated arms holding the tool guidemay be placed in a special clutched mode. In some examples, when one ofthe articulated arms holding the tool guide is placed in a clutched modeby the medical personnel, that articulated arm may be manually moved bythe medical personnel. To avoid placing undue strain on the tool guideand the articulated arms, the articulated arm holding the other end ofthe tool guide may be placed in a following mode where one or more jointactuators of the articulated arm holding the other end of the tool guideare driven based on the constrained kinematics of the tool guide and theclosed kinematic loop including the tool guide and the two articulatedarms holding the tool guide. In some examples, a position and/ororientation of a gantry of the computer-assisted medical device may beadjusted based on manual movement imposed by the medical personnel sothat each of the articulated arms may be moving at the same time. Insome examples, one or more forces and/or torques in the articulated armsholding the tool guide may also be monitored to reduce force and/ortorque detected during process 455. In some examples, when the joints ofthe tool guide include one or more actuators, these one or moreactuators may also be driven during process 455. In some examples, thevarious kinematic relationships and corresponding Jacobian transposesmay be used to convert the observed forces and/or torques into positionand/or orientation adjustments of the one or more joint actuators.

At a process 460, the tool guide is placed. Based on the medical toolinsertion path and pose determined during process 440, the tool guide isplaced so that the guide hole of the tool guide is positioned and/ororiented in alignment with the medical tool insertion path and locatedat as suitable distance from the target. In some examples, the suitabledistance may be determined based on a length of the medical tool to beused with the tool guide and/or to provide a stop that may limit adistance along which the medical tool may be inserted toward the target.

In some embodiments, the tool guide may be placed semi-automaticallyunder the direction of medical personnel. In some examples, a specialclutching mode, similar to the clutching mode used during process 455may be used during the semi-automatic placement. To aid the medicalpersonnel with the placement, the computer-assisted medical device mayoverlay one or more visual cues on images showing the computer-assistedmedical device and/or the patient. In some examples, the one or morevisual cues may depict a conical and/or other shape converging to thedesired position and/or orientation for the tool guide. In someexamples, the visual cues may include depiction of a virtual renditionof the medical tool and a desired position and/or orientation of themedical tool. In some examples, haptic feedback may be used to directthe tool guide to the desired position and/or orientation. In someexamples, when the joints of the tool guide include one or moreactuators, these one or more actuators may also be driven during process460.

In some embodiments, the tool guide may be placed automatically. In someexamples, constrained trajectory planning between the two articulatedarms may be used to automatically direct the tool guide to the desiredposition and/or orientation. In some examples, the constrainedtrajectory planning may include planning a trajectory for one of thearms holding the tool guide and placing the other articulated armholding the tool guide in the special clutching mode described duringprocess 455 using following and/or force and/or torque reduction. Insome examples, when the joints of the tool guide include one or moreactuators, these one or more actuators may also be driven during process460. In some examples, the automatic placement may support a manualoverride control that allows medical personnel to abort the automaticplacement.

At a process 465, the articulated arms holding the medical tool arelocked. Once the tool guide is placed during process 460, it is readyfor use by medical personnel. To avoid changes in the position and/ororientation of the tool guide and the guide hole, the joints of thearticulated arms holding the tool guide may be locked. In some examples,the joints may be locked using one or more braking mechanisms thatresist motion in the articulated arms. In some examples, the activejoints of the articulated arms holding the tool guide may also be drivento maintain the desired position and/or orientation of the tool guideand the guide hole.

At a process 470, the medical tool is placed in the tool guide. Once thetool guide and the guide hole are placed and aligned to the targetduring process 465, medical personnel may insert the appropriate medicaltool through the guide hole.

At a process 475, the medical tool is advanced to the target. Once themedical tool is placed in the tool guide during process 470, the medicaltool may be advanced to the target. In some examples, the medical toolmay be advanced through the guide hole until it reaches the target.

At a process 480, a procedure is performed. Once the medical tool hasreached the target during process 475, it is ready for use. In someexamples, the use may include percutaneous ablation including RF, cryo,microwave, and/or other forms of ablation), percutaneous needle biopsy,bone drilling, pedicle screw placement, seed planting, marker placement,medicine delivery, high magnification imaging, micro surgery, and/or thelike. In some examples, the tool guide may be actively moved insynchronization with a physiological motion of the patient such as thephysiological motions associated with respiration, heart beats, and/orthe like in order to maintain the tool guide and the guide hole alignedwith and/or at a desired distance from the target. In some examples,images captured from an imaging device, such as imaging device 270, maybe used to detect the physiological motion by noting changes in positionand/or orientation of one or more markers associated with the patient.In some examples, the detected physiological motion may be used todetect changes in the patient to computer-assisted medical devicekinematic relationship, which may be used as feedback to adjust one ormore of the actuators in the articulated arms and/or end effectorsholding the tool guide to maintain a constant tool guide to patientkinematic relationship.

In some embodiments, portions of the method 400 may be repeated asappropriate. In some examples, one or more of the processes 405-480 maybe repeated to change the target, switch medical tools, switch toolguides, and/or the like.

As discussed above and further emphasized here, FIG. 4 is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, additional controlapproaches may also be supported by the computer-assisted medical devicewhile working with a tool guide. In some examples, the computer-assistedmedical device may monitor the patient table to allow for changes inposition and/or orientation of the patient table. In some examples, thecomputer-assisted medical device may monitor the state of the table tomedical device kinematic relationship (e.g., table to device-basekinematic relationship 365) and adjust the other kinematic relationships(e.g., kinematic relationships 370, 372, 374, 376, and/or 378) in orderto keep the tool guide to patient kinematic relationship constant and/orto automatically account for the movement of the patient table. In someexamples, this monitoring may allow for automated adjustment of the toolguide without repeating processes 435-475).

In some embodiments, any of processes 470, 475, and/or 480 may beperformed automatically. In some examples, the medical tool may be anend effector of an additional articulated arm of the computer-assistedmedical device. In some examples, the additional articulated arm may beused to place the medical tool (i.e., the additional articulated arm'send effector) in the tool guide, advance the medical tool to the target,and/or perform the procedure. In some examples, a tool guide with adifferent configuration than tool guide 100 may be more suitable forautomating processes 470, 475, and/or 480 using the additionalarticulated arm.

FIGS. 5A and 5B are simplified diagrams of a top and side view ofanother tool guide 500 for use with two articulated arms and/or endeffectors according to some embodiments. As shown in FIGS. 5A and 5B,tool guide 500 includes a rigid or mostly rigid body 510 with anelongated shape. At a first end of body 510, tool guide 500 includes ajoint 520 that couples body 510 to a mounting arm 530. In some examples,joint 520 and mounting arm 530 may be similar to the joints 130 andmounting arms 140. As further shown in FIGS. 5A and 5B, the joint 520includes a two degree of freedom universal joint allowing independentrotation of mounting arm 530 relative to body 510 along two separateaxes. In some examples, the inclusion of joint 520 adds additionaldegrees of freedom to a closed kinematic chain including tool guide 500.In some examples, these additional degrees of freedom may providegreater flexibility in positioning the articulated arm and/or endeffector that is holding tool guide 500. And although FIGS. 5A and 5Bdepict joint 520 as a two degree of freedom universal joint, otherconfigurations are possible. In some examples, joint 520 may be aball-in-socket joint. In some examples, joint 520 may include zeroand/or one degree of freedom and/or may include a more complexarrangement of joints and links providing more than two degrees offreedom. In some examples, joint 520 may be passive, may include varyinglevels of resistance to motion, and/or may include one or more actuatorsmaking joint 520 an active joint. In some embodiments, joint 520 mayinclude one or more sensors for determining a position, orientation,force, and/or torque of joint 520. In some embodiments, joint 520 mayinclude one or more sensors for determining a position, orientation,force, and/or torque of joint 520. In some examples joint 520 may belockable (e.g., by a manually-tightened friction feature) to temporarilyprevent joint 520 from moving. In some embodiments, joint 520 maybenefit from a variable stiffness joint mechanism using materials andtechniques such as electro-rheological (ER) and/or magneto-rheological(MR) fluids.

In some embodiments, mounting arm 530 may include one or more featuresto help support use of tool guide 500 with the articulated arm and/orend effector. In some examples, the end of mounting arm 530 oppositejoint 520 may include a standardized attachment arrangement designed tomate with specific articulated arms and/or end effectors. In someexamples, the standardized attachment may provide a rigid, non-slipattachment between tool guide 500 and the articulated arms and/or endeffectors. In some examples, mounting arm 530 may include one or morenotches, flanges, clips, and/or the like suitable for attaching mountingarm 530 to an articulated arm and/or end effector. In some examples, byattaching tool guide 500 to the articulated arm using mounting arm 530,tool guide 500 becomes an end effector for the articulated arm. In someexamples, mounting arm 530 may include suitable identifying features sothe articulated arm and/or end effector to which mounting arm 530 isattached may identify mounting arm 530 as belonging to tool guide 500and may further identify a model number of tool guide 500. In someexamples, the identifying features may include one or more physicalpatterns, electrical contacts, magnets, RFID devices, and/or the like.In some examples, mounting arm 530 may further include electrical and/orphysical contacts for allowing the articulated arms and/or end effectorsto read the sensors and/or command the actuators in the joint 520.

In contrast to tool guide 100, which has guide hole 120, second joint130, and second mounting arm 140, tool guide 500 includes a tool sleeve540 at a second end of the body 510 opposite joint 520 and mounting arm530. Tool sleeve 540 includes a shaft with a hole 550 along its lengththrough which a medical tool is inserted in the direction of arrow 560.In some examples, tool sleeve 540 may have a tapered portion that mayhelp align the medical tool while it is being inserted into tool sleeve540 and which may also act as a stop to prevent further insertion of themedical tool when a wider upper portion with a matching taper on themedical tool reaches the tapered portion. In some examples, the toolsleeve may be detachable, such as with a snap fit, to allow differenttool sleeves with different lengths, diameters, and/or tapered profilesto be used with tool guide 540. In some examples, tool sleeve 540 may bedesigned to have a standardized size and profile to be used withcommonly used end effectors of a computer-assisted medical device, suchas the computer-assisted medical device described in FIG. 2 . In someexamples, tool sleeve 540 may be a cannula designed to be inserted at asite on a patient where an incision has been made.

In some embodiments, tool sleeve 540 may be associated with a mount 570.Similar to the mounting arm 530, mount 570 may include a standardizedattachment arrangement designed to mate with specific articulated armsand/or end effectors. In some examples, the standardized attachment mayprovide a rigid, non-slip attachment between tool guide 500 and thearticulated arms and/or end effectors. In some examples, mount 570 mayinclude one or more notches, flanges, clips, and/or the like suitablefor attaching mount 570 to an articulated arm and/or end effector. Insome examples, mount 570 may be designed to rigidly attach tool guide500 to an articulated arm and/or end effector while still permitting thearticulated arm and/or end effector to operate the medical tool insertedin tool sleeve 540. In some examples, mount 570 may include suitableidentifying features so the articulated arm and/or end effector to whichmount 570 is attached may identify mount 570 as belonging to tool guide500 and may further identify a model number of tool guide 500. In someexamples, the identifying features may include one or more physicalpatterns, electrical contacts, magnets, RFID devices, and/or the like.

In some embodiments, tool guide 500 may further include a memory device(not shown). In some examples, the memory device may be used to storeinformation associated with tool guide 500 including tool guide type,tool guide identification number, tool guide model number, tool guidekinematic parameters, and/or the like. In some examples, the storedinformation may be read by the computer-assisted system upon connectionof either the mounting arm 530 and/or the mount 570 to one of thearticulated arms and/or one of the end effectors. In some examples, theread information may be used by the computer-assisted system to identifytool guide 500, set control parameters, access the kinematic parameters,and/or the like. In some examples, the memory device may be accessedusing the electrical contacts, RF communication, and/or the like. Insome examples, the memory device may be accessed using the electricalcontacts, RF communication, and/or the like. In some examples, thememory device may include a machine readable media, such as RAM, PROM,EPROM, FLASH-EPROM, any other memory chip or cartridge, and/or any othermedium from which a processor or computer is adapted to read.

In some embodiments, mounting arms 530 and/or mount 570 may be used toprovide electrical power to tool guide 500. In some examples, theelectrical power may be used to operate the sensors, drive theactuators, control stiffness of the joint 520 via ER and/or MR fluids,and/or the like.

In some embodiments, tool guide 500 may be designed to be used where themedical tool inserted into tool sleeve 540 is an end effector mounted onthe distal end of an articulated arm. That is, in some configurationstool guide 500 is mounted to a first and second arm via mounting arm 530and mount 570 respectively, a medical tool is attached to the second armholding mount 570, and the medical tool is inserted through the toolsleeve 540 so that the first arm supports the tool sleeve 540 mounted tothe second arm. In some examples, tool guide 500 may provide the sameadvantages as tool guide 100 including improved rigidity, stiffness, andvibration resistance while one of the articulated arms holding the toolguide is also used to hold and actuate the medical tool inserted intotool sleeve 540.

In some embodiments, tool guide 500 may be used in place of tool guide100 while performing method 400 with little or no modification. The toolsleeve 540 may be inserted through an incision in the patient while thefirst articulated arm is placed in a clutched mode. A second articulatedarm may then be deployed near mounting arm 530 by using the kinematicrelationships of the first articulated arm and tool guide 500. A processsimilar to process 440 may then be used to attach mounting arm 530 tothe second articulated arm. In some examples, tool guide 500 may then befurther placed using a process similar to process 460. In some examples,medical personnel may then operate the medical tool end effector withthe second articulated arm being placed in a following mode, similar tothe following modes of process 455 and/or 460, where the secondarticulated arm helps adjust a position and orientation of tool guide500 and tool sleeve 540 to support the desired motions of the medicaltool while also steadying the first articulated arm and/or reducingvibration in the medical tool.

As discussed above and further emphasized here, FIGS. 1 and 5 are merelyexamples which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, additionalconfigurations are possible for tool guides 100 and/or 500. In someexamples, guide hole 120 of tool guide 100 may be replaced with a toolsleeve similar to tool sleeve 540 to better support use of a tool guideheld by two articulated arms and providing support for a medical tooloperated by a third articulated arm. In some embodiments, hapticfeedback may be employed whenever medical personnel are manipulating themedical tool.

Some examples of control units, such as control unit 280 may includenon-transient, tangible, machine readable media that include executablecode that when run by one or more processors (e.g., processor 285) maycause the one or more processors to perform the processes of method 400.Some common forms of machine readable media that may include theprocesses of method 400 are, for example, floppy disk, flexible disk,hard disk, magnetic tape, any other magnetic medium, CD-ROM, any otheroptical medium, punch cards, paper tape, any other physical medium withpatterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chipor cartridge, and/or any other medium from which a processor or computeris adapted to read.

Although illustrative embodiments have been shown and described, a widerange of modification, change and substitution is contemplated in theforegoing disclosure and in some instances, some features of theembodiments may be employed without a corresponding use of otherfeatures. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. Thus, the scope of theinvention should be limited only by the following claims, and it isappropriate that the claims be construed broadly and in a mannerconsistent with the scope of the embodiments disclosed herein.

What is claimed is:
 1. A tool guide for use with a computer-assistedmedical device, the tool guide comprising: an elongated body comprisinga first end and a second end opposite the first end; a joint attached tothe first end of the elongated body; a mounting arm coupled to theelongated body via the joint; and a tool sleeve attached to the secondend of the elongated body; wherein the mounting arm is configured to beattached to a first articulated arm of the computer-assisted medicaldevice; and wherein the tool sleeve is adapted to receive an endeffector attached to a second articulated arm of the computer-assistedmedical device.
 2. The tool guide of claim 1, wherein: the mounting armis configured to mate to the first articulated arm in a rigid andnon-slip arrangement.
 3. The tool guide of claim 1, wherein: the jointis selected from a group consisting of a two degree of freedom universaljoint and a ball-in-socket joint.
 4. The tool guide of claim 1, furthercomprising: a memory in which is stored one or more items of informationselected from a group consisting of tool guide type, tool guideidentification number, tool guide model number, and tool guide kinematicparameters.
 5. The tool guide of claim 1, wherein: the tool sleevecomprises a cannula.
 6. The tool guide of claim 1, wherein: at least aportion of the tool sleeve has a tapered shape.
 7. The tool guide ofclaim 1, wherein: the mounting arm comprises identifying informationidentifying the tool guide as a tool guide.
 8. The tool guide of claim7, wherein: the identifying information includes a model number.
 9. Thetool guide of claim 1, wherein: the tool sleeve is removably attached tothe body.
 10. The tool guide of claim 9, wherein: the tool sleeve isremovably attached to the body via a snap fit.
 11. The tool guide ofclaim 1, further comprising: a mount coupled to the tool sleeve, themount including an attachment configured to mate with the secondarticulated arm.
 12. The tool guide of claim 11, wherein the attachmentis configured to rigidly couple the second articulated arm to the toolsleeve.
 13. The tool guide of claim 11, wherein the mount includes anidentifying feature associated with the tool guide.
 14. Acomputer-assisted medical device comprising: a control unit comprisingone or more processors and memory; a first articulated arm comprising afirst joint and a distal end; a second articulated arm comprising asecond joint; and a tool guide comprising: an elongated body comprisinga first end and a second end opposite the first end, a third jointattached to the first end of the elongated body, a mounting arm coupledto the elongated body via the third joint and coupling the tool guide tothe distal end of the first articulated arm, and a tool sleeve attachedto the second end of the elongated body; wherein the tool sleeve isadapted to receive an end effector attached to the second articulatedarm; and wherein the memory comprises instructions to command thecontrol unit to operate the first joint to steady the end effector andto operate the second joint to position and orient the end effectorrelative to a target.
 15. The medical device of claim 14, wherein: thememory comprises instructions to command the control unit to operate thefirst and second joints so as to position the end effector to limit adistance the end effector may be advanced toward the target.
 16. Themedical device of claim 14, wherein: the memory comprises instructionsto command the control unit to use constrained kinematics of the toolguide to steady the end effector.
 17. The medical device of claim 14,wherein: the tool sleeve comprises a cannula.
 18. The medical device ofclaim 14, further comprising: a mount coupled to the tool sleeve, themount including an attachment configured to mate with the secondarticulated arm.
 19. The medical device of claim 18, wherein: theattachment is configured to rigidly couple the second articulated arm tothe tool sleeve.
 20. A computer-assisted medical device, comprising: acontrol unit comprising one or more processors and memory; a firstarticulated arm comprising a first joint and a distal end; a secondarticulated arm comprising a second joint; a third articulated arm towhich an imaging device is mounted; and a tool guide comprising: anelongated body comprising a first end and a second end opposite thefirst end, a third joint attached to the first end of the elongatedbody, a mounting arm coupled to the elongated body via the third jointand coupling tool guide to the distal end of the first articulated arm,and a tool sleeve attached to the second end of the elongated body;wherein the tool sleeve is adapted to receive an end effector attachedto the second articulated arm; and wherein the memory comprisesinstructions to command the control unit to: operate the first joint tosteady the end effector and to operate the second joint to position andorient the end effector relative to a target; and use one or more imagesobtained from the imaging device to determine a kinematic relationshipbetween the target and the computer-assisted medical device and tooperate the first and second joints based on the kinematic relationship.